According to Mark Schapiro, a staff writer at the Center for Investigative Reporting Inc. in Oakland, Calif., a $400 million security system "of a size and scope unprecedented in American history" is to be created to shield the controversial missile from Soviet surveillance. The Air Force doesn't deny that it's planning to spend such a sum of money on MX security.

Under a deployment plan drawn up by the Carter administration, 200 missiles would be shuttled by huge transporters among 4,600 shelters in the great Basin region of Nevada and Utah. Each one would sit somewhere in a cluster of 23 shelters.

Filling the remaining 22 shelters to prevent Soviet agents and satellites from locating the MX would be dummy or decoy missiles, simulating the weight and , to a greater or lesser degree, the "signatures" that the real missile would emit, such as acoustic or infrared characteristics.

Not all those conversant with the MX system are convinced that its missiles can be hidden from prying Soviet eyes. "It is not always easy to practice deception in this age of advanced intelligence technology," declares Herbert Scoville, president of the Arms Control Association, in his new book "MX: Prescription for Disaster." The Air Force disagrees.

Apart from sowing the MX fields with dummy missiles, the deployment area will be protected by a vast electronic surveillance network, "coordinated with intensified FBI monitoring activities . . . and . . . with special CIA counterinfiltration programs," asserts Schapiro.

"Constitutional attorneys claim that these plans could pose a sweeping threat to civil liberties in the region, and may entail an ominous transfer of legal authority from civilian to military hands," he observes in an article prepared by the Center for Investigative Reporting Inc. for the Washington-based Fund for Constitutional Government. Once again the Air Force disagrees, insisting that its jurisdiction is confined to its own property, namely the 2 1/2 acres around each missile shelter.

In his article, which the Air Force admits is 90 to 95 percent accurate, Schapiro asserts that:

* A 2,500-man security force of military policemen will patrol the MX missile system and its perimeter 24 hours a day.

* SWAT (Special Weapons and Tactics) teams will be on constant alert in the deployment area.

* Radar towers and other highly sensitive surveillance equipment, such as magnetic detectors and seismic and acoustic sensors, will monitor the movements of people and vehicles.

The Air Force is confident that such a security system will keep out any interlopers, particularly those in the pay of the Soviet KGB or Eastern Bloc intelligence agencies, which it seems to regard as a greater threat to the MX system than satellite surveillance.

But in a recent report that reviewed MX basing options, the Office of Technology Assessment (OTA), a research arm of Congress, suggested that the security network envisaged by the Air Force might not be sufficiently pervasive. It hinted that areas other than those immediately surrounding each missile shelter might have to be declared off limits to the public.

The OTA, moreover, expressed some doubts as to the Air Force's ability to conceal the real missiles among the dummies, or in MX jargon to ensure "preservation of location uncertainty" (PLU).

Deeming PLU the equivalent of a new technology, the OTA said it could not be confident of its success before MX prototypes are field tested, "because even fine details of missile signatures are important for adequate missile concealment." And it continued: "Furthermore, after the system is fully designed , tested, and deployed, lingering doubts could remain that would limit confidence in the system."

The Air Force begs to differ, pointing out that the OTA was not permitted access to "very deeply classified material" and therefore cannot know all the PLU techniques that will be employed.

Not only must the Air Force duplicate the weight of the 1.6-million-pound missile, launcher, and transporter system, but it must successfully mask or duplicate any observable "signatures" they give off. There are between 20 to 25 , say Air Force experts, and they include temperature, sound, weight, and smell. "Random is the key," says a Pentagon official, explaining that dummy missiles will not simply duplicate the signature levels of the real missiles but vary them for maximum obfuscation. The Air Force apparently has no doubt that its PLU measures will baffle Soviet strategic warfare chiefs.

Philip Klass, one of the country's foremost experts on satellite surveillance (and Aviation Week &amp; Space Technology magazine's senior avionics editor), says he is convinced a lot of thought has gone into the PLU question. "But I would not be so bold as to say that our planners and our scientists have been able to anticipate every conceivable thing."

Colin Gray, director of national security studies at the Hudson Institute in New York and a noted authority on the MX, points out that even if the Soviet Union could detect the location of some missiles, that ability would not invalidate the whole system. "The fact that you think you may have located some of them, I suspect, would not be good enough. Obviously, we'd like 100 percent assurance they haven't located any of them. But from the point of view of an attacker they probably require 100 percent guarantee they know where 90 percent of them are." This knowledge, he explains, would be vital because the dicision to launch a first strike on the US would be "the most important military decision in Russian history."

The administration is expected to announce its decision on deploying the MX next month.Defense Secretary Caspar Weinberger is thought to favor air launching of the missile from huge aircraft that can stay aloft for up to two days. But this basing concept has reportedly been rejected by the prestigious Townes Commission that was convened earlier this year to consider just how to deploy the MX.